There are different types of transmissions and control systems available depending on the nature or requirements of the transmission being used for an application. The main options available are a fully manual/standard type transmission with a manually operated clutch for slippage, an automatic type transmission with a torque converter for slippage and some sort of automatic shifting mechanism for gear changing without full operators input or a semi-automatic/clutchless manual which uses more operator input than an automatic yet still operates a mechanical clutch between the engine and transmission automatically for slippage.
Manual or standard shift vehicles are typically driven with a multi-speed transmission that transmits rotational drive from an engine to the axles of the vehicle. The transmission is movable through several speeds at the control of a manually linkaged stick shift. In a typical transmission, a number of gears are individually engaged to provide the several speeds. In a typical manual transmission, toothed shift collars slide to engage selected gears with an output shaft. When the gears are engaged rotational drive is transmitted from the engine to the transmission. The gears and collar transmitting rotational drive carry a high torque load, which makes it difficult if not impossible for an operator to manually move the collar out of pedal, thus breaking the drive connection between the engine and the transmission. The operator is then able to easily move the gear out of engagement. To complete a shift, the operator must first move the present gear selection out of engagement as previously described using the clutch pedal into a neutral position, where the engine to transmission connection is lost, manually move the shifter lever into another gear selection and release the clutch pedal re-engaging the engine to transmission connection again.
The main benefit of a manual/standard shift style transmission is complete driver control over gear selections and shift timing. This is due to the manual selector near the operator that is not influenced by anything other than a decision made and implemented solely by the operator. This is very useful when the operator sees the upcoming events while driving and can operate the transmission out of normal sequential gear sequence to prepare the vehicle for the torque load or speed requirement that is about to occur. For example an undesirable sharp gradient/downhill slope can create an excessive speed if not regulated. This can make a turn or stop dangerous if attempted. Instead of relying solely on the vehicles brakes and chancing the overheat and brake fade, the driver can downshift quickly even out of normal sequence for aid of engine braking to maintain or regulate safer speeds without worry of overheating and possibly losing the braking system.
Some of the flaws of a manual shift style transmission are: (i) Inconsistent clutch slippage (launch or start off) that is due to human operator error; (ii) even with the aid of internal transmission synchronizers, which help to mechanically synchronize gearing in and out of engagement, sometimes downshifting more than one gear out of sequence can feel clunky, be difficult or if not timed properly can be missed and left without the engine to transmission connection completely; (iii) Undesirable time gaps between the gear selections cause a problem in racing situations where having the lowest time for a run or lap is the main objective; (iv) undesirable back and forth rocking of a vehicle during the gear changing process can be discomforting to the operator or the passengers of the vehicle if any; (v) excessive wear of driveline components due to the, sometimes even harsh, disengaging and re-engaging of the engine to transmission connection; (vi) excessive amount of attentive work from the operator to simply drive or operate the transmission. Many timed/synchronous operations are needed to be performed by the operator during normal operation. If the operations are not performed timely or correctly much damage can be done to the transmission or other components.
Automatic shifting transmissions are also driven with a multi-speed transmission that transmits the rotational drive from an engine to the axles of a vehicle. The transmission is movable through its several speeds at the control of mainly two different automatic methods. The older method uses internal centrifugal force induced components and/or engine vacuum induced components along with hydraulics. The newer method uses computer controlled solenoids/servos/actuators in valve bodies that operate hydraulics. The different gear ratios are used to achieve and overcome the different torque requirements and/or speeds. In a typical automatic transmission, much more is going on inside and out than in a typical manual transmission. Different sets of constantly meshed gearing are used with applicators for each set to achieve the different gear ratios. Applicators are usually individual sets of “clutch to steel” clutch packs, band brakes for rotating drums or a combination of both, however the manufacturer designed the specific transmission. The applicators are powered on and off hydraulically. A transmission fluid pressure pump, usually internal, is driven by the constantly running engine that the transmission is mounted to. This supplies pressure to the valve body that directs the fluid pressure to the proper applicators to make the desired gear ratios/selections. What decides the valve body fluid direction is either the older designed centrifugal force induced governors and/or engine vacuum operated solenoids or an electronically programmed controller that uses inputs from the operator and the vehicle, i.e. vehicle speed and engine load signal from an engine computer, to determine and execute the different gear ratios needed for the constantly changing torque and/or speed requirements.
Benefits of an automatic transmission are: (i) no synchronizers needed due to all the gearing always meshed and applicators used for the engaging and disengaging, making it almost impossible for the transmission to “miss a shift”; (ii) much lower, if not completely eliminated, time gaps between gear selections makes the transmission, and entire vehicle, more consistent which is a large benefit for racing purposes where time and predictability matters most; (iii) back and forth motions are eliminated due to throttle on gear changes since the engine to transmission connection is never lost during the gear change; (iv) consistent slippage ratio due to a fluid type torque converter instead of a clutch makes for consistent and predictable stop to go launches/start offs and smoother shifting gear changes; (v) extended maintenance life of other driveline components due to the constant forward rotational torque without unloading driveline motion during gear changes; and (vi) very little work for the operator to continuously operate the transmission, simply choose either Park, Reverse, Neutral or Drive/Forward and the rest is done by itself.
A flaw of an automatic transmission is that the driver can predict an upcoming event but the automatic transmission cannot. It can only work off of the real time inputs it is given and make any changes it seems is necessary. The driver does not have the full control of out of sequence gear selections if desired, i.e. quick out of sequence down shifting for engine braking on an undesirable downhill. Even with aftermarket full manual valve bodies with active, and sometimes clunky, gear shifters there still is only sequential shifting.
A semi-automatic, also known as a “clutchless manual” or “flappy paddle” style gearbox, is an actual clutch style manual gearbox or transmission with electronics and/or pneumatics to move what an operator used to move manually by themselves. It changes gears using electronic sensors, processors, actuators and pneumatics on the command of a driver and computer combined. This style transmission control system has eliminated the need for a clutch pedal, since the clutch itself is actuated by electronic equipment that can synchronize the timing and torque required to make quick and smooth launches/start offs and gear changes.
A benefit of the semi-automatic style transmission is it can make consistent launches/start offs and fairly smooth shifts like an automatic with more operator control, yet less effort than a full manual style transmission with the manually operated clutch.
Some flaws of the semi-automatic transmission are: (i) even though the launches/start offs are more consistent than a manual with a clutch pedal, it still isn't as consistent as the automatic due to the input, process and output timing needed for the processing and driving of actuators versus the natural reaction of the torque converter in the automatic; and (ii) only sequential shift changes available; (iii) uses a full mechanical clutch with zero slippage even at lower engine speeds where changing gears up or down can create the undesirable rocking. This can be both a possible loss of traction during racing applications or uncomfortable for daily drivers. Some manufacturers use a communication to the engine computer to momentarily halt power output either with ignition retarding or throttle closing to smooth out the between gear changes. This helps smooth but does not help in racing applications where full power is always desired and at the control of the driver only.
All transmissions and transmission control systems have applications where one is better than another in that particular application. However, an operator may desire: (i) less necessary effort to continually operate than a manual with clutch style system; (ii) more control over shift timing and gear selection than what an automatic or semi-automatic system can provide; (iii) more consistent launching/start offs than the semi-automatic or manual clutch style system can provide; (iv) unmissable yet “on the throttle” shifts, that the manual clutch style and semi-automatics that halt power between gear changes cannot provide; and (v) no delay between gear changes, which the semi-automatic or manual with clutch style both cannot provide.
Therefore, there is a need in the art for a transmission control system that allows the operator full control to effortlessly, yet quickly, shift gear selections in either a sequential or non-sequential manner while retaining consistent launching capabilities than any of the transmission control systems alone can provide. These and other features and advantages of the present invention will be explained and will become obvious to one skilled in the art through the summary of the invention that follows.